1. Field of the Invention
The present invention relates to dumbbells and relates more particularly to a dumbbell which can be conveniently adjusted to change its weight.
2. Description of Prior Art
Conventionally, a dumbbell is simply comprised of a short bar of wood or iron with heavy ends, used in exercising the arms. This structure of dumbbell has a fixed total weight once it was made. Because the total weight is not adjustable, different dumbbells shall be used for different amounts of exercise. In order to solve this problem, there is disclosed a weight adjustable dumbbell, as shown in FIG. 1, which is generally comprised of a short bar having a plurality of pin holes symmetrically spaced on two opposite ends thereof for releasably fastening different pairs of round weights by lock pins. One disadvantage of this weight adjustable dumbbell is that the round weights may oscillate on the two opposite ends of the short bar as it is lifted or swung about in the hand for muscular exercise, causing a balancing problem. Another disadvantage of this weight adjustable dumbbell is that the lock pins may disconnect from the short bar or be broken easily causing the round weights to suddenly displace from respective positions or drop from the short bar, and therefore an exercising accident may happen easily.